Survey to check on a builder's roofing work

[Burrower]

Theoretically this shouldn't be a DIY question, but it's becoming one.

I've had most of our house re-roofed by a builder, but am becoming a bit suspect as to the quality of the work. He's already been back to fix some issues (twice now) and I've also fixed another issue myself; seemed less hassle than waiting for him to do it.

I'm concerned there are more problems and am considering whether it's worth getting a survey company to produce a report on the roof. Given my concerns, is this the best course of action?

Thanks in advance.

 

[OwainDIYer]

A local RICS Chartered Surveyor can be instructed to survey the roof work but make sure they are told that the report may be used as evidence in a claim against the builder so they can prepare it accordingly.

 

[^woody^]

Think about how the roof will be accessed to allow the surveyor to look at things properly. If the roofer was a member of a trade body, such as the NFRC, then contact them.

 

[Burrower]

I'm fairly sure the builder is not a member of any trade body.

How much should I expect to pay for a roofing survey? The roof is mainly slate. The house is a largish 3-bed house, 1.5 storey with two dormers. Plan view is a T-shape i.e. an (old) extension sticking out the back (the stalk of the T, hope that makes sense). There is also a modern one storey tiled extension at the front.

B.